1. Technical Field
The present invention generally relates to a rotary developer and an image formation apparatus that is provided with the rotary developer. The rotary developer to which the invention is directed performs development by turning a rotary unit so as to set each of development cartridges at a predetermined development position in a sequential manner after the development cartridges having a plurality of colors are attached to the rotary unit. The image formation apparatus having the rotary developer according to the invention includes electro-photographic apparatuses such as an electrostatic process copying machine, an electro-photographic printer, an electro-photographic facsimile, just to name but a few with no intention of limitation thereto.
2. Related Art
Generally speaking, a full-color image formation apparatus having a rotary developer is provided with a rotary unit to which four-ink-color development cartridges are attached. A typical example thereof is disclosed in JP-A-10-153911. In the configuration of such a rotary developer, each of the development cartridges is inserted into the rotary unit from the insertion side thereof along a direction parallel to the rotation axis thereof so as to fix it at a predetermined “set” position. In the operation of such a rotary developer, when one development cartridge that is the current target of development is set at a predetermined development position by means of the rotational movement of the rotary unit, it is necessary to align the position thereof with a photosensitive member, which is an image carrier, with a high positional accuracy. In addition, it is further necessary to hold the development cartridges securely so that they cannot move undesirably in the axial direction of the rotary unit during its rotation, or due to any other similar reason.
According to the configuration of the rotary developer described in JP-A-10-153911, the development cartridges are simply attached at the predetermined set positions of the rotary unit. Therefore, it is difficult to effectively prevent the development cartridges from moving in the axial direction thereof during the rotation of the rotary unit. Moreover, a user might fail to securely attach the development cartridges at the predetermined set positions of the rotary unit.